The invention relates to an automated bag filling machine and method of operation therefore in which a chain of interconnected reclosable plastic bags are individually opened, filled, closed, and separated from the chain for packaging and, more particularly, to improvements in such a machine and method whereby changeover from an operation of filling bags of one size to a operation of filling bags of a different size is possible in a quick and simplified manner.
Prior to the instant invention, mechanisms for automatically feeding, loading, and sealing plastic bags have been devised. Prior art arrangements of this type are shown, for example, in U.S. Pat. No. 3,477,196 and U.S. Pat. No. 3,952,480. Both of these patents relate to mechanisms for conducting in seriatim a series of plastic bags, originally opened at one mouth end and connected together in a bag chain, to a loading station where the bags are individually loaded with material deposited through their open mouth ends and then to a closing station where the mouth ends of the bags are individually closed by heat sealing means.
No automatic bag loading mechanism has heretofore been commercialized to handle reclosable lock plastic bags of the type disclosed, for example, in U.S. Pat. No. 3,198,228 and presently manufactured by Minigrip, Inc., of Orangeburg, N.Y. This form of bag has closed bottom end and side edges and a reclosable upper end mouth having interlocking fastener strip rib and groove profiles running across inner facing surfaces of the mouth. The nature of manufacture and operation of the reclosable plastic bags present all together different handling problems than those presented by bags arranged for heat seal closing. For instance, reclosable fastener plastic bags are typically closed at their mouth ends during the manufacture process in order to allow proper interfitting of the rib and groove members and exit the manufacturing site in that closed condition. The bag mouths must be opened at a loading site to permit filling and then closed again for packaging.
Heretofore known automatic bag loading devices, such as disclosed in U.S. Pat. No. 3,477,196 and U.S. Pat. No. 3,952,480, are not capable of feeding, filling, and sealing reclosable fastener strip plastic bags, since the bag handling mechanisms of these devices are not conducive or adaptable to the unique characteristics of the reclosable bags.
It has been necessary to provide manual loading of reclosable lock bags, making such a loading operation very expensive in terms of labor costs and requiring much time since the loader must first manually open the initially closed bag, deposit fill material into the bag, manually interlock the bag near mouth fastener strip profiles, and finally transfer the loaded bag to a packaging station. U.S. Pat. No. 3,744,211 discloses an automatic bag filling apparatus for handling reclosable fastener strip profile bags connected together in a chain; however, this mechanism is not known to be commercialized and calls for the use of a one-step spring force to pull apart the interlocked fasteners of an empty bag in order to permit filling. Due to the rather delicate nature of plastic bags, this one-step opening action would probably often lead to undesirable tearing of the bag material so as to not be all together commercially practical.
The corresponding co-pending application Ser. No. 429,617 concerns a method and apparatus for feeding, opening, loading, and reclosing fastener strip profile plastic bags in an automated fashion, such that the filling operation can be accomplished quickly, inexpensively, and reliably given the relatively delicate nature of plastic bags. The machine disclosed in that application, however, is set for handling bags of a predetermined, substantially common width size and does not enable the operator to readily change over operation to handle bags of a different size.
The present invention relates to an automated bag filling machine specifically adapted to handle a chain of bag elements of the reclosable fastener strip profile type, which can be readily adjusted to change over operation to handle bags of different sizes within a range of sizes and which permits quick, inexpensive, and reliable feeding, opening, loading, and reclosing of this type of plastic bag.